1. Field of Use
This invention relates generally to a valve construction for releasing a relatively large volume of pressurized gas into a storage vessel containing granular material and the like for the purpose of accelerating the flow of said granular material therefrom and more particularly to modifying such valve construction for improved operation.
2. Description of Prior Art (Background)
Discharging particulate material from an opening in a storage vessel is sometimes troublesome because of clogging, bridging, rat-holing or sticky build-up of the particulate material on the vessel walls, which can occur anywhere in the vessel but usually occurs near the discharge outlet of the vessel. This clogging is often aggravated when the particulate material is moist or contains additives that make it sticky. Numerous attempts have been made in the past to alleviate this problem. For example, it has been proposed to mount one or more gas discharge devices on the vessel walls or sloping sides of hoppers containing particulate material. Such discharge aid devices have a nozzle extending into the hopper for directing a blast of gas into the hopper to reduce clogging and bridging of the material contents so that the material can be discharged by conventional gravity or to assist other unloading equipment as disclosed in U.S. Pat. No. 3,788,527. While such prior art discharge aid devices, such as air blasters or air pulsing, have met with varying degrees of commercial success, the devices all have open discharge ends which are subjected to particulate material and fines entering into the devices via said openings and fouling the internal mechanisms and rendering the devices partially or completely inoperative. This shortcoming of the prior art devices necessitates shutdowns for costly repair, cleaning and loss of production.
Also by the nature of construction for said prior art devices, close tolerances of the internal piston member to the surrounding outer housing are necessary for these air blasters to operate efficiently. This creates a problem where temperature changes in the surrounding environment can cause binding between parts having different thermal expansion coefficients, thereby causing eventual operational failure. These temperature variations can be seasonal or daily, caused by changing environmental conditions, or created by the industrial processes involved.
A related serious problem occurring with operation of these prior art valve constructions is that of contaminating the stored particulate material with metal pieces derived from the valve itself or its mounting plate, such as weldment bits.
An aerator valve of this type now in wide commercial use has also been developed having fewer moving parts than disclosed in the aforementioned prior art patent. Unfortunately, said modified valve construction still remains prone to much of the above noted operational difficulties attributable at least in part to having critical components fabricated with weldments. Basically, said modified valve construction includes an outer housing with front and back ends terminating a central inner passageway, a movable piston member slidably engaged within the central passageway in said outer housing, a spring loaded piston guide member affixed within the central passageway in said outer housing intermediate the front and back ends, and a pneumatic valve mechanism supplying a pressurized gas medium to drive the piston member forward unseating the front end of said passageway and releasing the pressurized gas to the surrounding atmosphere. In constructing said commercial valve device, the piston member is designed with an enlarged head termination sealing the front end of the central passageway and with said member having been formed with multiple component parts joined together by conventional welds. More particularly, a machined rod is employed which is threaded into and welded to a separate enlarged head portion of said member and with the enlarged head portion further terminating with a welded end cap. Still further welding of a metal compression spring to the spring loaded piston guide member employed in said valve construction occasions frequent device failure during valve operation accompanied by introducing weld fragments into the storage vessel where employed.
To overcome the aforesaid operational difficulties with this type valve device, there is now provided an improved pneumatic powered gas discharge valve construction having few internal parts and which can still further be affixed to assorted storage vessels in an improved manner. In doing so, the present valve device can be connected to a high flow pulse type electric solenoid valve for installation on one or more storage vessel side walls to direct repeated pulses of the pressurized gas medium being released between the particulate material being stored and the inner vessel wall. Multiple installations of the presently improved valve device are contemplated with individual valves being equally spaced about the side walls of said storage vessel when desired. Affixing of the presently improved valve construction to a storage vessel side wall or multiple side walls has also been simplified for cost reduction and required maintenance or valve removal. More particularly, the prior art valve installations customarily employ a flat mounting plate coupled to another flat mounting flange in order to physically secure the valve device to the vessel side wall and with the vessel side wall often having a curved contour requiring considerable welding to accomplish such manner of joinder. As distinct therefrom, the presently improved valve construction enables joinder of said valve device to the vessel side wall with a novel weld-on mounting collar.
It is an object of the present invention, therefore, to provide an operationally improved gas powered discharge aid device having fewer non-welded internal working parts.
It is another object of the present invention to provide said presently improved gas discharge device in a manner requiring only a relatively simple modification of the component parts.
A still further object of the present invention is to provide improved means whereby the presently improved gas discharge device can be physically secured to the side walls of a storage vessel.
It is yet another object of the present invention to provide a novel cooperation between the presently improved gas discharge device and the mounting means whereby said device can be physically secured to a storage vessel side wall.
These and still further objects of the present invention will become apparent upon considering the following detailed description of the present invention.